But he's got a few things to contend with first: he is starving, his chiropractor will be arriving soon, and he desperately needs to catch a few more hours of sleep on the bus.

It's no surprise that life on the road can run the gamut from exhilarating to tedious to downright taxing. At this point in their career, Mastodon have passed through each stage several times over. In the past few years they've crisscrossed the globe and gained serious industry cred and fan support, but they've also endured rough patches that included life-threatening injuries and the death of loved ones. As it turns out, those difficult times inspired them to break free from concept records and create one of their most visceral and upbeat records of their career.

The roots of The Hunter can be traced back to the intense circumstances surrounding the creation of their epic concept album Crack the Skye, and its subsequent tour. That album was heavy, both musically and conceptually. Hinds composed the album as he recuperated from serious head trauma he received in a fight, while the lyrics dealt, in part, with the suicide of drummer Brann Dailor's sister when she was 14.

Crack the Skye was brought to life each night through a series of vignettes that were projected behind the band and synchronized to the music. "It was a very intense thing to do," Hinds says. "Everything was on a click track, and there was no room for error at all. After a while that became really nerve wracking."

The stress also caught up with Kelliher in early 2010, when he experienced a flare-up of his acute pancreatitis (for which he was first hospitalized in November 2008) and required more treatment. "Crack the Skye came at a really dark period," Kelliher says. "First Brent was in the hospital, and then I was in the hospital. We were like, 'Shit, we're getting old and shit is breaking down!'" he says, laughing.

After taking some time off to rest, Mastodon headed back out on the fall 2010 Blackdiamondskye tour with Alice in Chains and Deftones, an experience that would be crucial to the direction of The Hunter. "Alice in Chains are really great, positive guys," Kelliher says. "Going on tour with them really lifted our spirits. Everyone in our band was in a good mood. It was like our batteries were recharged, which helped us change some things up for this record and reinvent ourselves a bit. Like, 'Hey, we don't have to be the band that just writes concept albums."'

"During that tour, no one got fucked up," Hinds says. "Well, except the guys in the Deftones. Instead of going, 'Let's get totally wasted,' we were playing guitar all day, so we were a lot more productive. Bill would be backstage with his recording setup, and when he left I'd just take over."

Free from excessive partying, and no longer bound to an overall musical theme or narrative, the guitarists adopted a new, productive routine in which they worked on tracks independently and followed them through to the recording process. "Brent and I weren't getting together and writing," Kelliher says. "It was more like Brent wrote some stuff with Brann, and I wrote some stuff with Brann. In fact I didn't even play on some of the album, and the same with him."